Instagram API Returns invalid format for Callback_Url error

I am using Instagram API .

I am trying a simple record for a subscription request and I keep getting

"Invalid format for 'callback_url'. URL must start with http: // or https: .//"

It clearly begins with this.

I can not find anyone who works in the same problem.

Tried a message with a clear callback url:

http://api.instagram.com/v1/subscriptions/?client_id={client_id}&client_secret={secret}&object=tag&aspect=media&object_id=skateboarding&callback_url=http://skateparkoftampa.com/spot/instagram_callback.aspx

And with the HTML callback URL:

http://api.instagram.com/v1/subscriptions/?client_id={client_id}&client_secret={secret}&object=tag&aspect=media&object_id=skateboarding&callback_url=http%3A%2F%2Fskateparkoftampa.com%2Fspot%2Finstagram_callback.aspx

I also tried this with both GET and POST, and also allowed the API console to create a request by simply filling in the parameter fields, etc. I feel like I'm missing something really obvious or something else, but I'm stuck. Any ideas?